Global Advanced Research Journal of Medicine and Medical Sciences (ISSN: 2315-5159) Vol. 7(4) pp. 085-089, April, 2018
Available online http://garj.org/garjmms
Copyright © 2018 Global Advanced Research Journals
Full Length Research Article
Diagnostic accuracy study of loop mediated isothermal
amplification in the detection of Mycobacterium
tuberculosis in Pakistan
Asim Saeed*, Afreenish Hassan, Umme Farwa, Shahid Ahmad Abbasi and Asim Ali Shah
Microbiologist National Institute of Health, Islamabad, Pakistan, Senior Pathologist/Microbiologist Excel Labs (Pvt) Ltd
Accepted 20 April, 2018
The study has been conducted in Armed Forces Institute of Pathology, Rawalpindi Pakistan from 2015
to 2017. The study was done to determine the adequacy of Loop-mediated Isothermal Amplification for
the detection of Mycobacterium tuberculosis. A cross sectional study was done on 72 clinical sputum
samples taken from the patient suspected of tuberculosis using a novel technique LAMP targeting
IS6110 gene sequence for the first time in Pakistan. Six primers recognizing eight distinct regions on the
target sequence were employed. The assay was performed in total volume of 25 µl containing primers,
DNA polymerase, Fluorescent dye and sample incubated at 65°C for 60 minutes along with positive and
negative controls. LAMP amplicons were detected by their fluorescence under UV light and compared
with gold standard MGIT culture system and smear microscopy. Out of 72 total samples 60(83.3%) were
LAMP positive and 61(84.7%) were MGIT positive. Its specificity, sensitivity is 100% and 98.36%
respectively with PPV 100% and NPV 91.6%. According to our study the LAMP assay is suggested to be
a potential nucleic acid based diagnostic method for TB detection in developing countries.
Keywords: Loop Mediated Isothermal Amplification (LAMP), IS6110 gene, Mycobacterium tuberculosis.
Mycobacterium Growth Indicator Tube (MGIT)
INTRODUCTION
Tuberculosis (TB) caused by Mycobacterium
tuberculosis, is a highly contagious disease and a major
public health issue. Each year more than 8.6 million new
cases and 1.3 million consequent deaths due to TB have
been reported; mainly affecting population in developing
countries (Organization, 2013). TB has been rampant for
decades and Pakistan is ranked 6th amongst the TB
high-burden countries in the world (Khan et al., 2016).
The incidence of sputum smear positive TB cases is
*Corresponding Author E-mail: dr.asimch@gmail.com;
Cell: +923145183024
80/100,000 per year and for other sample types it is
estimated 177/100,000; which constitutes in Pakistan 5.1
percent of the cumulative national disease burden
(Vermund et al., 2009). Besides efficient therapeutic
regimes, rapid, accurate, and low-cost laboratory
diagnostic methods are urgently needed to control TB
and to reach the misdiagnosed cases (Bi et al., 2012;
Organization, 2013).
There are many methods, at present, for diagnosing TB
including Ziehl-Neelsen staining (ZN), conventional
culturing on Lowenstein–Jensen (LJ) medium,
Mycobacterium growth indicator tube (MGIT) culture,
PCR, TB gold and T spot (Ryu, 2015); these are either
less specific and sensitive, time consuming, expensive or